2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------From: Paul Mackerras <paulus@samba.org>

upstream commit: 306a82881b14d950d59e0b59a55093a07d82aa9a

Richard Henderson pointed out that the powerpc __futex_atomic_op has abug: it will write the wrong value if the stwcx. fails and it has toretry the lwarx/stwcx. loop, since 'oparg' will have been overwrittenby the result from the first time around the loop. This happensbecause it uses the same register for 'oparg' (an input) as it usesfor the result.